DE112021007110T5 - ACTIVE INPUT PEN, POSITION DETECTION SYSTEM AND INTEGRATED CIRCUIT - Google Patents

Abstract

TaskPrevent drawing by a pen input from stopping due to an error in receiving an uplink signal.SolutionAn active stylus 2 according to the present invention has a processing circuit 26d which, at a time, using the reception time of an uplink signal US received from a sensor controller 31 was decided as a reference timing, transmits a position signal and a data signal from a pen tip electrode 21 and receives a next uplink signal, and a wireless communication unit 28 that performs short-distance wireless communication with the sensor controller 31. The processing circuit 26d determines whether or not the next uplink signal has been received at that time, and the processing circuit 26d sends at least a part of the data signal via the wireless communication unit 28 in a case where it is determined that the next uplink signal has not been received. while sending the position signal from the pen tip electrode 21.

Description

Technical area

The present invention relates to an active stylus, a position detection system and an integrated circuit, and more particularly to an active stylus that communicates mutually and bidirectionally with a sensor controller, an integrated circuit for such an active stylus, and a position detection system comprising such an active stylus and a sensor controller .

General state of the art

An active stylus pen designed to bidirectionally send/receive signals to/from a sensor controller in a position detection device through an electrode (hereinafter referred to as a “pen tip electrode”) provided on a pen tip is known. Hereafter, the communication performed by the pen tip electrode in this manner will be referred to as “pen tip communication”. Additionally, the signal sent from the sensor controller to the active stylus will be referred to as the “uplink signal” and the signal sent from the active stylus to the sensor controller will be referred to as the “downlink signal”.

The downlink signal serves as a position signal to cause the sensor controller to detect the position of the active stylus and as a data signal to send data in the active stylus to the sensor controller. The sensor controller that performs the pen tip communication is configured to detect the position of the active stylus based on the reception strength of the downlink signal at each of a plurality of sensor electrodes provided in a touch surface and to pass through the data sent by the active stylus Demodulating the downlink signal detected at any of the sensor electrodes. The position detected by the sensor controller and the data received from it are provided to a host processor and used for drawing by pen input.

In addition, in recent years, an electronic pen suitable for short-distance wireless communication such as Bluetooth (registered trademark) has appeared. Patent Documents 1 and 2 disclose examples of a so-called electronic pen. The electronic pen described in Patent Document 1 is designed to make initial settings based on information received from a position detection device through short-distance wireless communication and to provide pen pressure information, side switch information and identification information through short-distance wireless communication can send. In the electronic pen described in Patent Document 2, short-distance wireless communication is used to switch the function of the electronic pen from “drawing” to “erasing,” for example.

State of the art documents

Patent documents

• Patent Document 1: Japanese Patent Publication No. 6487782
• Patent Document 2: US Patent No. 9,924,019

SUMMARY OF THE INVENTION

Technical problem

Incidentally, the sensor controller is configured to periodically transmit the uplink signal, and the active stylus is configured to transmit the downlink signal using the reception timing of the uplink signal as a reference timing and receive a next uplink signal. Therefore, for the active stylus to function normally, it is necessary that the uplink signal has been received.

However, in some cases, the uplink signal is overwhelmed by noise such as a signal to drive pixels of a display, for example, and as a result the active stylus may not be able to receive the uplink signal. The active input pen is then unable to send at least the downlink signal as a data signal. This is because the sensor controller and the active stylus must be synchronized with each other in order for the sensor controller to receive the data signal correctly. Improvements were needed because pen input drawing stops when the active stylus cannot send the data signal.

Therefore, one of the objects of the present invention is to provide an active stylus, a position detection system and an integrated circuit that can prevent drawing by a pen input from stopping due to an error in receiving an uplink signal.

Additionally, a conventional sensor controller determines whether or not the active stylus is in contact with the touch surface based on a pen pressure value included in the data signal. Hereafter, the information indicating the determination result will be referred to as “contact state information”. The contact state information is information indicating either a state in which the active stylus is not in contact with the touch surface (a floating state) or a state in which the active stylus is in contact with the touch surface (a contact state).

However, in the above determination method, since the transmission of the data signal by the active stylus is performed intermittently, there may be a delay in updating the contact state information by the sensor controller. In addition, in a case where the active stylus sends the data signal via short-distance wireless communication instead of via the pen tip communication, a communication delay also causes a delay in updating the contact state information.

Therefore, another object of the present invention is to provide an active stylus and a position detection system that can suppress the occurrence of a delay in updating the contact state information by the sensor controller.

Technical solution

An active stylus according to a first aspect of the present invention is an active stylus including a signal processing unit that transmits a position signal and a position signal at a time determined using a reception time of an uplink signal received from a sensor controller as a reference time data signal from a pen tip electrode and receiving a next uplink signal, and a first wireless communication unit that performs short-range wireless communication with the sensor controller. The signal processing unit determines whether or not the next uplink signal has been received at the time, and the signal processing unit, in a case where it is determined that the next uplink signal has not been received, sends at least a part of the data signal via the first wireless communication unit while sends the position signal from the pen tip electrode.

A position detection system according to the first aspect of the present invention is a position detection system including the active stylus and the sensor controller. The sensor controller outputs data indicated by the data signal sent by the active stylus from the pen tip electrode and data indicated by the data signal sent by the active stylus via the first wireless communication unit as data from the same active stylus to a host processor.

An integrated circuit according to the first aspect of the present invention is an integrated circuit used for an active stylus pen having a first wireless communication unit for performing short-range wireless communication with a sensor controller. At a timing decided using a reception timing of an uplink signal received from the sensor controller as a reference timing, sending a position signal and a data signal from a pen tip electrode and receiving a next uplink signal are performed. It is determined whether or not the next uplink signal has been received at the time, and in a case where it is determined that the next uplink signal has not been received, at least a part of the data signal is transmitted via the first wireless communication unit while the position signal sent from the pen tip electrode.

An active stylus according to a second aspect of the present invention is an active stylus that includes a processing circuit that generates a downlink signal to be sent to a sensor controller, and a transmitting circuit that sends the downlink signal by subjecting it to a potential of an electrode is provided on a pen tip, conveys a change. The processing circuit performs a carrier modulation process in which the downlink signal is generated based on a first carrier signal in a case where the active stylus is in a contact state, while the downlink signal is generated in a case where the active stylus is in a Floating state is generated on the basis of a second carrier signal that differs from the first carrier signal.

A position detection system according to the second aspect of the present invention is a position detection system including the active stylus and the sensor controller. The sensor control determines whether a carrier signal is one Downlink signal received from the active stylus is the first carrier signal or the second carrier signal, and determines whether or not the active stylus is in contact with a touch surface based on the result of the determination.

Beneficial effect

According to the first aspect of the present invention, even if the uplink signal is not received and the active stylus cannot send the data signal from the pen tip electrode, the sensor controller can receive the position of the active stylus using the position signal sent from the pen tip electrode and receive the active stylus transmission data via short-range wireless communication. Therefore, it is possible to prevent drawing by pen input from being stopped due to an error in receiving the uplink signal.

According to the second aspect of the present invention, since the contact state information can be sent by the carrier signal of the downlink signal, it is possible to suppress the occurrence of a delay in updating the contact state information by the sensor controller.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1 : 1 is a diagram showing a structure of a position detection system according to a first embodiment of the present invention.
• 2 : 2 is a state transition diagram of a processing circuit 26d of an active stylus 2.
• 3 : 3A is a diagram showing the format of an uplink signal US, 3B , and 3C are diagrams each representing the format of a downlink signal DSa, 3D is a diagram showing the format of a downlink signal DSb, and 3E is a diagram showing the format of a downlink signal DSc.
• 4 : 4 is a processing flowchart showing a process performed by the processing circuit 26d of the active stylus 2.
• 5 : 5 is a processing flowchart showing a process performed by the processing circuit 26d of the active stylus 2.
• 6 : 6 is a processing flowchart showing a process performed by a sensor controller 31.
• 7 : 7 is a processing flowchart showing a process performed by the sensor controller 31.
• 8th : 8th is a processing flowchart showing a process performed by the sensor controller 31.
• 9 : 9 is a processing flowchart showing a process performed by the sensor controller 31.
• 10 : 10 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 of a second embodiment of the present invention.
• 11 : 11 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 according to a modification example of the second embodiment of the present invention.
• 12 : 12 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 of a third embodiment of the present invention.
• 13 : 13 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 according to a modification example of the third embodiment of the present invention.
• 14 : 14 is a diagram for illustrating signals sent and received between the active stylus 2 and the sensor controller 31 when transmitting and receiving the uplink signal US and the downlink signal DS are carried out in time slot units.

WAYS OF CARRYING OUT THE INVENTION

Preferred embodiments of the present invention are described below Reference to the accompanying drawings will be described in detail.

1 is a diagram showing a structure of a position detection system 1 according to a first embodiment of the present invention. As in 1 As shown, the position detection system 1 has an active input pen 2 and an electronic device 3, which is a position detection device for detecting the active input pen 2.

The electronic device 3 is, for example, a computer with a touch surface 3a such as a tablet computer or a digitizer. Inside the electronic device 3, a sensor 30 disposed directly under the touch surface 3a, a sensor controller 31 connected to the sensor 30, a display 32 disposed to superimpose on the sensor 30, are one wireless communication unit 33 (a second wireless communication unit) and a host processor 34 for controlling each unit of the electronic device 3 having these units.

The host processor 34 is a central processing unit of the electronic device 3 and is designed to read and execute various types of programs from a memory not shown. The programs executed in this way include various types of applications including an operating system of the electronic device 3 and a drawing application. Among them, the drawing application is a program for executing a process of generating digital ink based on the position and data supplied from the sensor controller 31 and storing it in the memory in the electronic device 3 and a process of reproducing the generated ones digital ink, for generating a video signal indicating the result and supplying it to the display 32. The display 32 is a display for displaying a video signal supplied from the host computer 34, and has, for example, a liquid crystal display or an organic one Electroluminescent display (EL display).

The sensor controller 31 is an integrated circuit having the function of deriving the position of the active stylus 2 in the touch surface 3a by bidirectionally communicating with the active stylus 2, acquiring data from the active stylus 2, and the derived position and the acquired data each Time to deliver to the host processor 34. Basically, the communication between the sensor controller 31 and the active stylus 2 is carried out via the pen tip communication described above, but short-range wireless communication is also used depending on the situation.

In particular, the communication from the sensor controller 31 to the active stylus 2 is carried out via the pen tip communication. Hereafter, the signal sent from the sensor controller 31 to the active stylus 2 for this communication will be referred to as the “uplink signal US”. On the other hand, the communication from the active stylus 2 to the sensor controller 31 is basically carried out via the pen tip communication, but along with it, short-range wireless communication is used only in a case where the active stylus 2 cannot receive the uplink signal US. Hereinafter, the signal sent by the active stylus 2 that has successfully received the uplink signal US via the pin tip communication will be referred to as “downlink signal DSa”, the signal sent by the active stylus 2 that has not received the uplink signal US could be sent over the pin tip communication, be called “downlink signal DSb”, and the signal sent through the short-range wireless communication by the active stylus 2, which could not receive the uplink signal US, be called “downlink signal DSc”.

The sensor 30 is a device having a structure in which a plurality of sensor electrodes are arranged in the touch surface. The pen tip communication is carried out via communication according to a capacitive coupling method, which is performed by the capacitance formed between the plurality of sensor electrodes and electrodes (a pen tip electrode 21 and a ring electrode 22, which will be described later) on the active stylus 2 side becomes. The sensor controller 31 sends the uplink signal US by imparting a change to the potential of each sensor electrode, while detecting the downlink signals DSa and DSb by detecting a change in the potential of each sensor electrode.

Here, some of the multiple sensor electrodes that make up the sensor 30 may be used as a common electrode (an electrode to provide a common ground potential to each pixel) of the display 32. An electronic device 3 employing such usage is generally referred to as an “in-cell type” position detection device. Otherwise, an electronic device 3 that does not make this use constitutes what is generally referred to as a position de detection device of the “on-cell type” or the “out-cell type”. The present invention is preferably applicable to any electronic device 3.

The wireless communication unit 33 is, for example, a communication device for performing short-range wireless communication such as Bluetooth (Registered Trademark), and is connected to the sensor controller 31 and the host processor 34. The host processor 34 performs control of the wireless communication unit 33 including pairing with the communication partner, and performs short-range wireless communication for general-purpose use such as connecting a keyboard, a mouse, a speaker and a headphone through the wireless communication unit 33. Meanwhile, the sensor controller 31 uses the wireless communication unit 33 to receive the downlink signal DSc via the short-range wireless communication.

As in 1 As shown, the active stylus 2 has a core body 20, a pen tip electrode 21, a ring electrode 22, a pressure sensor 23, a side switch 24, a battery 25, an integrated circuit 26, a barrier filter 27 and a wireless communication unit 28 (a first wireless communication unit ) on. The core body 20 is an element that forms the pen shaft of the active stylus 2. The tip of the core body 20 forms the pen tip of the active input pen 2, and its end rests on the pressure sensor 23. The pen tip electrode 21 and the ring electrode 22 are conductors provided at positions different from each other in the pen tip. More specifically, the pen tip electrode 21 is disposed at the tip of the core body 20 of the active stylus 2, and the ring electrode 22 is disposed at a position closer to the center of the active stylus 2 with respect to the pen tip electrode 21 in such a manner that the core body 20 surrounds.

The pressure sensor 23 is a sensor that detects a pressure applied to the tip (pen tip) of the core body 20. The pressure detected by the pressure sensor 23 is supplied to the integrated circuit 26 as a 12-bit pen pressure value, for example. The side switch 24 is a push button switch provided on the surface of the active stylus 2 and is designed to be turned on and off by the user. The operating state (the on/off state) of the side switch 24 is provided to the integrated circuit, for example, as 2-bit switch information. The battery 25 serves to supply the electrical current that is necessary for the operation of the integrated circuit 26.

The wireless communication unit 28 is, for example, a communication device for performing short-range wireless communication such as Bluetooth (registered trademark). The active stylus 2 uses the wireless communication unit 28 to send the downlink signal DSc to the sensor controller 31.

The integrated circuit 26 is an integrated circuit having various circuits including an amplifier circuit 26a, a transmission circuit 26b, a reception circuit 26c and a processing circuit 26d. The transmitting circuit 26b is connected to the pen tip electrode 21 and serves to transmit the downlink signals DSa and DSb by imparting a change to the potential of the pen tip electrode 21 using the amplifier circuit 26a. The receiving circuit 26c is connected to the ring electrode 22 and serves to receive the uplink signal US by detecting a change in the potential of the ring electrode 22.

The processing circuit 26d is a circuit (a signal processing unit) that executes a process in response to the uplink signal US received by the receiving circuit 26c. This process includes a process of deciding the transmission/reception schedule of the downlink signal DS and a next uplink signal US using the reception timing of the uplink signal US as a reference timing, a process of generating the downlink signal DS according to a command from the sensor controller 31, and causing the Transmitting circuit 26b or the wireless communication unit 28 transmits the generated downlink signal DS, and a process of causing the receiving circuit 26e to receive the next uplink signal US.

2 is a state transition diagram of the processing circuit 26d. As in 2 As shown, the processing circuit 26d is configured to operate in any one of a detection mode, a normal mode, and a dual transmission mode. The initial state is the detection mode, and the processing circuit 26d having entered the detection mode continuously or intermittently causes the receiving circuit 26c to perform an operation of detecting the uplink signal US (step S1).

If, as a result of the detection activity in step S1, the uplink signal US detect has been ted, the processing circuit 26c enters the normal mode (step S2). Then, the transmission/reception schedule of the downlink signal DS and the next uplink signal US is decided using the reception timing of the uplink signal US as the reference timing, and the transmission circuit 26b is made to transmit the downlink signal DSa following the decided schedule (step S10), and upon occurrence of the Receiving time of the next uplink signal US (step S11), the receiving circuit 26c is caused to carry out the operation of detecting the next uplink signal US (step S12). As a result, when the next uplink signal US has been detected (step S13), the transmission/reception schedule is decided again using the reception timing of the uplink signal US as the reference timing, and the process of step S10 is repeated.

On the other hand, in a case where the uplink signal US has not been detected as a result of the detection operation in step S12, the processing circuit 26d enters the dual transmission mode (step S14). The processing circuit 26d in the dual transmission mode generates the downlink signal DSb and causes the transmission circuit 26b to transmit the generated downlink signal DSb, and also generates the downlink signal DSc and causes the wireless communication unit 28 to transmit the generated downlink signal DSc (step S20). Furthermore, in step S20, the receiving circuit 26c is also caused to perform the operation of detecting the uplink signal US in parallel with transmitting the downlink signals DSb and DSc. This parallel process is carried out by the blocking filter 27, which is in 1 is illustrated, and details thereof will be described later.

When detection of the uplink signal US occurs in step S20, the processing circuit 26d returns to the normal mode (step S21). Then, the transmission/reception schedule is decided again using the reception timing of the uplink signal US as the reference timing, and step S10 is repeated. On the other hand, if the state of non-detection of the uplink signal US has continued for a predetermined time, the processing circuit 26d returns to the detection mode to continue the process (step S22). In this case, sending of the downlink signal DS stops.

Back to 1 . The processing circuit 26d includes an oscillator circuit that generates a clock signal having a predetermined frequency, and a frequency divider circuit that generates a carrier signal by dividing the frequency of the clock signal generated by the oscillator circuit. The predetermined frequency is, for example, 8 MHz. For example, in a case where the frequency dividing ratio of the frequency dividing circuit is 20, the frequency of the carrier signal is 400 kHz, which is obtained by dividing 8 MHz by 20. The processing circuit 26c is configured to generate the downlink signals DSa and DSb based on the carrier signal generated by the frequency divider circuit. In addition, the processing circuit 26d has a function of changing the frequency dividing ratio of the frequency dividing circuit.

The notch filter 27 is a filter circuit inserted between the ring electrode 22 and the integrated circuit 26 to enable detection of the uplink signal US, detection using the ring electrode 22, and transmission of the downlink signal DSb from the pin tip electrode 21 simultaneously. In particular, a change in the potential of the pen tip electrode 21, which change accompanies the transmission of the downlink signal DS, also affects the receiving circuit 26c, since the potential rise through the amplifier circuit 26a used to send the downlink signal DS reaches up to 18 to 20 V . As a result, since the potential of the uplink signal US detected by the receiving circuit 26c is superimposed on the downlink signal DS, it becomes difficult to detect the uplink signal US simultaneously with the transmission of the downlink signal DSb. In a case where the active stylus 2 is in a floating state (a state in which the pen tip is away from the touch surface 3a) and the ring electrode 22 is far from the sensor 30, the detection of the uplink signal US becomes more difficult. as the reception strength of the uplink signal US decreases. The notch filter 27 also serves to prevent the change in the potential of the pen tip electrode 21, which change accompanies the transmission of the downlink signal DSb, from affecting the potential of the uplink signal US detected by the receiving circuit 26c in the integrated circuit 26, thereby the detection of the uplink signal US, the detection using the ring electrode 22 and the transmission of the downlink signal DSb from the pin tip electrode 21 are enabled simultaneously.

Different types of designs can be used for the specific structure of the barrier filter 27. For example, in a case where the downlink signal DSb includes a sine wave-based signal, the notch filter 27 may include a band stop filter (notch filter) that blocks a specific frequency band containing the frequency of the downlink signal DSb. And in a case where the downlink signal DSb includes a pulse wave, the blocking filter 27 may also include a high-pass filter configured to block the pulse wave constituting the downlink signal DSb while the pulse wave constituting the uplink signal US. is allowed through. Further, in a rear stage of the high-pass filter, a mute circuit for muting the edge of the downlink signal DSb may be provided, or the downlink signal DSb may be provided by constructing the notch filter 27 using a combination of an amplification circuit and a differential circuit or a combination of a finite impulse response filter (FIR -Filter), a subtractor and a feedback circuit can be eliminated from the signal arriving at the ring electrode 22.

3A until 3E are diagrams showing the formats of the uplink signal US and the downlink signals DSa, DSb and DSc. If initially on 3A For reference, the uplink signal US includes local identifiers LID and NLID, a command COM and an error detection code CRC.

The local identifiers LID and NLID are identification information given by the sensor controller 31 to the active stylus 2, which becomes the partner of the pen tip communication. The active input pen 2, which has not yet started communication with the sensor controller 31, extracts the local identifier NLID from the uplink signal US detected as a result of the detection operation, and stores the extracted local identifier NLID as its own local identifier Pairing with the sensor control 31 to be carried out.

The COM command is information indicating a command for the active stylus 2. The local identifier LID located at the beginning of the COM command indicates the destination of the COM command. The active stylus 2, which has received the uplink signal US, first refers to the local identifier LID and determines whether the local identifier LID corresponds to the stored local identifier or not. As a result, in a case where it is determined that they correspond to each other, a process of generating a data signal DATA described later is performed following the COM command.

When next on 3B and 3C Referring to this, the downlink signal DSa includes a position signal POS1 and the data signal DATA. The position signal POS1 is an unmodulated carrier signal (a carrier signal generated by the frequency divider circuit described above) and is used by the sensor controller 31 to detect the position of the active stylus 2 on the touch surface 3a. The sensor controller 31 acquires the reception strength of the position signal POS1 at each of the plurality of sensor electrodes constituting the sensor 30 and detects the position of the active stylus 2 based on its distribution. Meanwhile, the data signal DATA is a signal obtained by modulating the carrier signal, which was generated by the frequency divider circuit described above, is obtained with data sent from the active stylus 2 to the sensor controller 31.

This in 3B Downlink signal DSa shown is a signal sent by the active stylus 2 immediately after storing the local identifier NLID described above. As in 3B As shown, the downlink signal DSa in this case has the local identifier LID, a global identifier GID and the error detection code CRC. Of these, the stored local identifier NLID is set as the local identifier LID. This point applies equally to other downlink signals DS to be described later. The global identifier GID is an identifier assigned to the active stylus 2 at the stage of delivery, and is used to inform the sensor controller 31 of the type, function, version, and the like of the active stylus 2. In a case where the downlink signal DSa has an unpaired local identifier LID, the sensor controller 31 extracts the local identifier LID and the global identifier GID therefrom and stores them in association with each other to pair with the active stylus 2.

The downlink signal DSa, which is in 3C is a signal sent by the active stylus 2 in a case where substantially no instruction is given by the COM command. The active stylus 2 is designed to periodically send the downlink signal DSa when substantially no instruction is given by the COM command. As in 3C is shown, the downlink signal DSa in this case has the local identifier LID, a pen pressure value PRE, a switchin formation SW and the error detection code CRC. The pen pressure value PRE is information received from the pressure sensor 23, which is in 1 is shown, is supplied to the integrated circuit 26, and the switch information SW is information indicating the operating state of the in 1 side switch 24 shown.

When next on 3D For reference, the downlink signal DSb includes only a position signal POS2, which is an unmodulated carrier signal similar to the position signal POS1. Since the downlink signal DSb is a signal sent when the active stylus 2 loses the transmission timing of the downlink signal DS (that is, when the active stylus 2 is not synchronized with the sensor controller 31), even when the data signal DATA is placed in It is not expected from the downlink signal DSb that the sensor controller 31 can carry out a correct demodulation. Meanwhile, since the position signal POS2, like the position signal POS1 described above, is used to detect the position of the active stylus 2 based on the distribution of reception strength at each of the plurality of sensor electrodes constituting the sensor 30, the sensor controller 31 needs this Position signal POS2 not to be demodulated, at least for the detection of the position. Therefore, in the present embodiment, the active stylus 2 is designed to send only the position signal POS2 as the downlink signal DSb, and thereby the sensor controller 31 can detect the position of the active stylus 2 even when the active stylus 2 and the sensor controller 31 are not connected to each other are synchronized.

However, in the present embodiment, the position signal POS2 also has the role of sending certain information to the sensor controller 31 within a scope that is possible even when the active stylus 2 and the sensor controller 31 are not synchronized with each other. The content of the specific information represents, for example, 1-bit information indicating whether the active stylus 2 is in contact with the touch surface 3a or not. This information is no less than the contact state information described above. In this case, the processing circuit 26d of the active stylus 2 obtains the contact state information based on the pen pressure value obtained from the in 1 pressure sensor 23 shown is supplied, determines whether the active input pen 2 is in contact with the touch surface 3a. Then, the position signal POS2 is modulated by any one of frequency modulation, spread spectrum and phase modulation based on the acquired contact state information.

Specifically, the processing circuit 26d first makes the frequency of the position signal POS2 different in a case where the frequency modulation is used by making the division ratio of the frequency dividing circuit described above to be different between the case where the active stylus 2 is used Touch surface 3a is in contact, and the case in which the active input pen 2 is not in contact with the touch surface 3a. In a typical example, it is preferable that the frequency division ratio is 20 in a case where the active stylus 2 is in contact with the touch surface 3a, and in a case where the active stylus 2 is not in contact with the touch surface 3a, 19 or 21 is. In this case, the frequency of the position signal POS2 is 400 kHz in the case where the active stylus 2 is in contact with the contact surface 3a, and the frequency of the position signal POS2 is 400 kHz in the case where the active stylus 2 is not in contact with the Touch surface 3a is in contact, 381 kHz or 421 kHz. The sensor controller 31 demodulates the information sent by the processing circuit 26d by detecting the frequency of the position signal POS2 using asynchronous detection.

In a case where the spread spectrum is used, the processing circuit 26d then generates the position signal POS2 using different spreading codes for the case where the active stylus 2 is in contact with the touch surface 3a and the case where the active stylus 2 is not in contact with the touch surface 3a. The sensor controller 31 continuously detects the spreading code contained in the position signal POS2, that is, the information sent by the processing circuit 26d, by correlating it with each of the two types of spreading codes used by the processing circuit 26d calculated.

Finally, in a case where phase modulation is used, the processing circuit 26d is designed to generate the position signal POS2 by changing the phase every predetermined period. Then, the processing circuit 26d sets the change amount of the phase to a different value depending on whether the active stylus 2 is in contact with the touch surface 3a or not. The sensor controller 31 demodulates the information sent by the processing circuit 26d by measuring the amount of change Phase detected using delay detection.

When the processing circuit 26d sends the contact state information as described above, the effect that occurrence of delay in updating the contact state information by the sensor controller 31 can be suppressed can also be obtained in the position detection system 1 according to the present invention. This point will be described in more detail later in a second embodiment, a third embodiment and modification examples thereof.

When next on 3E Reference is made, the downlink signal DSc contains given data including the local identifier LID assigned to the active stylus 2. It should be noted that various types of information corresponding to the low level of the protocol stack, such as the destination address and the source address of the short-range wireless communication, are added to the actual downlink signal DSc due to the fact that the downlink signal DSc is sent via short-range wireless communication , but in 3E A description of these information elements has been omitted and only the information that corresponds to the high level of the protocol stack is shown.

As in 3E is shown, the downlink signal DSc can be as shown in 3C Downlink signal DSa shown contains the pin pressure value PRE, the switch information SW and the error detection code CRC. Accordingly, the downlink signal DSc serves as an alternative transmission means in a case where the active stylus 2 is not synchronized with the sensor controller 31 and therefore these information items cannot be sent via the pen tip communication.

The sensor controller 31 is designed to output the positions detected by the downlink signals DSa and DSb and the data received by the downlink signals DSa and DSc as data from the same active input pen 2 to the host processor. More specifically, for each local identifier LID, the sensor controller 31 generates a data stream for supplying data to the host processor 34, and is designed to include the positions detected by the downlink signals DSa and DSb and the data detected by the downlink signals DSa and DSc were received, sequentially synthesized into the data stream. Accordingly, the host processor 34 can even process the data received by the sensor controller 31 via the short-range wireless communication in the same manner as the data received via the pen tip communication.

Here, since the downlink signals DSa and DSb are transmitted according to the transmission/reception schedule, the sensor controller 31 can obtain the local identifier LID indicating the sources of the downlink signals DSa and DSb based on the reception timings of the downlink signals DSa and DSb. Therefore, the sensor controller 31 can synthesize the position and transmission data of the active stylus 2 obtained from the downlink signals DSa and DSb into the corresponding data stream even if the local identifier LID is not arranged in the downlink signals DSa and DSb.

On the other hand, since the downlink signal DSc is transmitted regardless of the transmission/reception schedule, the sensor controller 31 cannot obtain the local identifier LID indicating the source of the downlink signal DSc even by referring to the reception timing of the downlink signal DSc. In principle, when the source address of the short-range wireless communication and the local identifier LID are stored in association with each other and the source address contained in the downlink signal DSc is referred to, it is possible to use the local identifier LID representing the source of the downlink signal DSc to obtain, but to do so, the sensor controller 31 must reference information corresponding to the low level of the short-range wireless communication protocol stack.

Since the local identifier LID is placed in the downlink signal DSc in the present embodiment, the sensor controller 31 can determine the local identifier LID indicating the source of the downlink signal DSc only from the information corresponding to the high level of the short-range wireless communication protocol stack . In this way, the sensor controller 31 can synthesize the transmission data of the active stylus 2 obtained from the downlink signal DSc into the corresponding data stream even without the sensor controller 31 referring to the information corresponding to the low level of the short-range wireless communication protocol stack.

The processes described so far are then described with reference to processing flow diagrams to illustrate the processes of the Processing circuit 26d and the sensor controller 31 will be described in more detail.

First of all are 4 and 5 Processing flowcharts showing the process performed by the processing circuit 26d of the active stylus 2. As in 4 As shown, the processing circuit 26d first enters the detection mode (step 5100). Then, the receiving circuit 26c is caused to perform the operation of detecting the uplink signal US (step S101), and as a result it is determined whether or not the uplink signal US has been received (step S102). Upon determining that the uplink signal US has not been received, the processing circuit 26d repeats the process from step S101. On the other hand, upon determining that the uplink signal US has been received, the processing circuit 26d enters the normal mode (step S103). Then, by extracting the local identifier NLID from the uplink signal US and storing it, pairing of the pen tip communication with the sensor controller 31 is performed (step S104).

Next, the processing circuit 26d acquires the short-range wireless communication address of the sensor controller 31 (step S105). This address is specifically the address of the wireless communication unit 33, which is in 1 is shown, and is determined in advance by a user activity in the processing circuit 26d. Subsequently, the processing circuit 26d determines whether the short-range wireless communication pairing with the device indicated by the acquired address has been established or not; if this is not the case, it performs the pairing of the short-range wireless communication with the device using the wireless communication unit 28 which is in 1 is shown (step S106).

Next, the processing circuit 26d decides the transmission/reception schedule of the downlink signal DS and a next uplink signal US using the reception timing of the last received uplink signal US as a reference timing (step S107), and executes transmission of the downlink signal DSa (step S107) following the decided transmission/reception schedule S108) and the activity of detecting the next uplink signal US (step S109). Then, it is determined whether the uplink signal US has been received as a result of step S109 (step S110), and if it is determined that it has been received, the processing circuit 26d repeats the process from step S107, whereas if it is determined that it was not received, enters the dual transmission mode (step S 120).

The processing circuit 26d, which has entered the dual transmission mode, generates the in based on the detected pen pressure value (the last pen pressure value provided from the pressure sensor 23). 3D position signal POS2 shown (step S121). That is, the position signal POS2 is generated by modulating the carrier signal based on whether or not the active stylus 2 is in contact with the touch surface 3a. Then, the processing circuit 26d continuously transmits the downlink signal DSb while continuously performing the operation of detecting the uplink signal US (step S122. This simultaneous receiving and transmitting is a process performed by the in 1 Blocking filter 27 shown can be implemented.

In addition, the processing circuit 26d determines whether the detected pen pressure value is 0 or a value greater than 0 (step S123), and if it is determined to be a value greater than 0, a process of sending the downlink signal DSc is performed. Specifically, if the wireless communication unit 28 is in the power saving mode, the wireless communication unit 28 is first switched to the normal mode (step S124), and then the downlink signal DSc is sent using the short-range wireless communication (step S125). If the wireless communication unit 28 has not been used for a long time, the wireless communication unit 28 enters the power saving mode and cannot communicate, and step S124 is a process to restore the wireless communication unit 28 to a communication-capable state in such a case. In addition, the reason why the downlink signal DSc is not sent in a case where the detected pen pressure value is 0 is a suppression of the power consumption caused by the wireless communication unit 28, since in the case where the detected pen pressure value is 0 is, no digital ink is generated and therefore there is little need for immediate sending of the pen pressure value or switch information.

Next, the processing circuit 26d determines whether or not the uplink signal US has been received through the detection operation performed in step S122 (step S126). As a result, upon determining that the uplink signal US has been received, the processing circuit 26d proceeds to step S103 4 over and returns to normal len mode to continue the process. On the other hand, when determining in step S126 that the uplink signal US has not been received, the processing circuit 26c determines whether or not a predetermined time has elapsed since the last reception of the uplink signal US (step S127). When it is determined that the predetermined time has not passed, the processing circuit 26d returns to step S121 to repeat the process of the dual transmission mode, whereas in a case where it is determined that the predetermined time has passed, the processing circuit 26d returns Step S 100 returns to enter the detection mode. Accordingly, it is possible to prevent the downlink signals DSb and DSc from being continuously transmitted even though the active stylus 2 has been disconnected from the electronic device 3.

Next are 6 until 9 Processing flowcharts showing the process carried out by the sensor controller 31. As in 6 As shown, the sensor controller 31 first decides the transmission/reception schedule of the uplink signal US and the downlink signal DS (step S200). The transmission/reception schedule decided here includes the transmission timing of the uplink signal US and the reception timing (the timing set using the transmission timing of the uplink signal as the reference timing) of the downlink signal DS for each local identifier LID. The transmission/reception schedule is predetermined in the protocol of an active capacitive method and is shared in advance by the sensor controller 31 and the active stylus 2.

Here, multiple transmission/reception schedules that differ depending on conditions such as the number of active stylus 2 detected can be prepared in advance, and the sensor controller 31 can change the transmission/reception schedule if the conditions are met. Then, each time a change is made, the COM command in the uplink signal US can be used to communicate to each active stylus 2 information indicating the transmit/receive schedule to be used. In this way it is possible to effectively use the communication resources of the active capacitive method. Furthermore, in a case where the electronic device 3 is of the above-mentioned in-cell type, the sensor controller 31 can set the transmission/reception schedule based on information regarding the driving period of the pixels of the display 32 obtained from the in 1 host processor 34 shown can be obtained, decide. In this way, it is possible to avoid an error in sending and receiving signals due to noise generated by the display 32.

Next, the sensor controller 31 determines whether or not the timing of sending the uplink signal US specified in the decided transmission/reception schedule has come (step S201), and upon determining that it has come, becomes the uplink signal US sent (step S202). On the other hand, if the sensor controller 31 has determined that it has not come, it determines for each local identifier LID whether the reception timings of the position signal POS1 and the data signal DATA have come (steps S203 and S204). If it is determined that none of the timings have come, the sensor controller 31 returns to step S201 to repeat the process. On the other hand, if it is determined that the reception time of the position signal POS1 has come, the process becomes that in 7 shown in step S210, and if it has been determined that the reception time of the data signal DATA has come, the process goes to that in 8th shown in step S220. Below is the process involved in 7 until 9 is shown using a case where the local identifier LID is equal to n, for example.

In step S210 of 7 The sensor controller 31 directs the command position of the active stylus 2 based on the received strength of the signal at each of the plurality of sensor electrodes that in 1 sensor 30 shown (step S210). Then, it is determined whether or not the command position of the active stylus 2 was successfully derived (step S211), and if it is determined that it could not be derived, the process goes to step S201 6 brought back. On the other hand, when it is determined that it has been successfully derived in step S211, the sensor controller 31 performs a demodulation process considering the received signal as the position signal POS2 and tries to convert the information sent by the processing circuit 26d of the active stylus 2. to obtain (step S212). If the information obtained in step S213 is information indicating the contact state (the state of contact with the touch surface 3a) of the active stylus 2, the sensor controller 31 now proceeds to step S230, which will be described later and in In a case where the data signal DATA could not be received, reference is made to this information. If the received signal is the position signal POS1 or any other signal, the information obtained in step S213 is none essential information, but there is no particular problem since the sensor controller 31 does not execute step S230 described later in this case.

Then, the sensor controller 31 generates a data stream with LID = n if it has not already been generated (step S214), and synthesizes the detected command position into the data stream with LID = n (step S215). Accordingly, the command position of the active stylus 2, which corresponds to LID = n, is delivered to the host processor 34.

In step S220 of 8th the sensor controller 31 selects a sensor electrode based on the last command position of the corresponding active stylus (step S220), and performs the operation of detecting the data signal DATA using the selected sensor electrode (step S221). Then, it is determined whether or not the data signal DATA has been detected (step S222).

When the sensor controller 31 has determined that the data signal DATA has been detected in step S222, it obtains the transmission data of the active stylus 2 by demodulating the detected data signal DATA (step S223). Subsequently, the sensor controller 31 determines whether or not the pairing of the pen tip communication with the active stylus 2 has been established with LID = n (step S224). If this has not been established, the global identifier GID is acquired from the data acquired in step S223 (step S225) and the pairing of the pen tip communication with the active stylus 2 by storing the acquired global identifier GID in association with LID = n carried out (step S226).

The sensor controller 31 further obtains the short-range wireless communication address corresponding to the global identifier GID (step S227). The address is in particular the address of the wireless communication unit 28, which is in 1 is shown, and is determined in advance by a user activity in connection with the global identifier GID of the active input pen 2 in the sensor controller 31. Then, the sensor controller 31 determines whether or not the pairing of the short-range wireless communication with the device specified in the acquired address has been established, and if not, instructs the host processor 34 to perform the pairing (step S228). The host processor 34, which received the instruction, executes using the in 1 shown wireless communication unit 33, the pairing of the short-range wireless communication with the address obtained by the sensor controller 31 in step S227.

When it is determined that the pairing has been established in step S224 or when step S228 has been completed, the sensor controller 31 synthesizes the data obtained in step S223 into the data stream with LID = n (step S229) and completes the process Step S201 of 6 back. When the sensor controller 31 executes step S229, the transmission data of the active stylus 2 corresponding to LID = n is delivered to the host processor 34.

If the sensor controller 31 has determined in step S222 that the data signal DATA has not been detected, it determines as in 9 shows whether the active input pen 2 is in contact or not (step S230). The determination is made based on the information provided by the sensor controller 31 in step S212 of 7 was obtained.

When the wireless communication unit 33 is in the power saving mode, the sensor controller 31, which has determined that the active stylus 2 is in contact in step S230, switches the mode to the normal mode (step S231), determines whether the data signal (the downlink signal DSc) with LID = n was received or not via the short-range wireless communication (step S232), and determines the result (step S233). It should be noted that step S231 is necessary for the same reason as step S124.

When the sensor controller 31 has determined that the data signal with LID = n has been received in step S233, it obtains the transmission data of the active stylus 2 corresponding to LID = n by demodulating the received data signal (step S234). Then, the acquired transmission data is synthesized into the data stream with LID = n (step S235), and the process goes to step S201 6 brought back. When the sensor controller 31 executes step S235, the host processor can continuously acquire the data sent by the active stylus 2 even if the active stylus 2 does not send the data signal DATA from the pen tip electrode 21 due to a failure in receiving the uplink signal US can, and can even continuously acquire the position of the active input pen 2 through step S215, so that drawing by the pen input can be continued.

As described above, in the active stylus 2 and the position detection system 1 according to the present embodiment, the sensor controller 31 can detect the position of the active stylus 2 even when the uplink signal US is not received and the active stylus 2 does not receive the DATA signal Pen tip electrode 21 can send, detect using the position signal POS2 sent from the pen tip electrode 21, and receive the transmission data of the active stylus 2 via the short-range wireless communication. Therefore, it is possible to prevent drawing by pen input from stopping due to an error in receiving the uplink signal US.

In addition, since the contact state information indicating whether or not the active stylus 2 is in contact with the touch surface 3a can be sent via the position signal POS2, it is possible to use the short-distance wireless communication in a case where drawing is performed by a Pen input is not performed, thereby making it possible to reduce the power consumption of the active stylus 2. In addition, it is also possible to obtain the effect that the occurrence of a delay in updating the contact state information by the sensor controller 31 can be suppressed.

Further, since the notch filter 27 is provided in the active stylus 2 and the operation of detecting the uplink signal US can be performed in parallel with transmitting the position signal POS2, it is possible to return the active stylus 2 from the dual transmission mode to the normal mode while doing so Position signal POS2 is continuously sent.

Next, a second embodiment of the present invention will be described in detail. In the present embodiment, the operation of the position detection system 1, which was also described in the first embodiment, will be described in more detail focusing on the point of suppressing the occurrence of delay in updating the contact state information by the sensor controller 31.

10 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting the position detection system 1 of the present embodiment. The horizontal axis in 10 is the timeline. In addition, every “frame” that is in 10 is shown, the transmission period of the uplink signal US and the sensor controller 31 is designed to send the uplink signal US at the beginning of each frame. These points also apply to 11 until 14 , which will be described later.

An in 10 Position signal POS2d shown is the position signal POS2 sent by the active stylus 2 when it is in the contact state, and a position signal POS2u is the position signal POS2 sent by the active stylus 2 when it is in the floating state . The processing circuit 26d according to the present embodiment is designed to be capable of generating at least two kinds of carrier signals having different frequencies by controlling the frequency dividing ratio of the frequency dividing circuit described above, and is designed to generate the position signal POS2d on the basis of a (first carrier signal) of the carrier signals is generated and the position signal POS2u is generated based on the other (second carrier signal) of the carrier signals. More specifically, the processing circuit 26d is configured to obtain an unmodulated first carrier signal as the position signal POS2d and obtain an unmodulated second carrier signal as the position signal POS2u.

The receiving circuit 26c of the active stylus 2 according to the example of 10 has successfully received the uplink signal US sent from the sensor controller 31 in the n-1th frame. In this case, the downlink signal DS sent by the processing circuit 26d is as shown in 10 shown that in 3B or 3C Downlink signal DSa shown. The processing circuit 26d sends the downlink signal DSa using the remaining time after receiving the uplink signal US and waits for the uplink signal US to be received at the beginning of the nth frame.

Then the receiving circuit 26c of the active input pen 2 succeeds according to the example of 10 in the nth frame fails to receive the uplink signal US sent by the sensor controller 31. In this case, the processing circuit 26c occurs as in 4 shown enters the dual transmission mode to transmit the downlink signal DSb, which is the position signal POS2, and thereby performs a process of modulating the carrier signal (hereinafter referred to as “carrier modulation process”) based on the last acquired contact state information. Specifically, in the case of the contact state, the position signal POS2d is generated, while in the case of the floating state, the position signal POS2u is generated, and the generated signal is sent as the downlink signal DSb.

In the example of 10 The contact state information of the active stylus 2 increases from the contact state at time t1 switched to the floating state and, in response, the processing circuit 26d sends the position signal POS2d up to the time t1 and the position signal POS2u after the time t1. The transmission of the position signal POS2d or the position signal POS2u is carried out until the uplink signal US is received or until a predetermined time has elapsed since the last reception of the uplink signal US, as referred to 4 was described.

The sensor controller 31 is configured to sequentially determine whether the carrier signal of the downlink signal DS received from the active stylus 2 is the first carrier signal or the second carrier signal, and determines whether the active one is active based on the result of the determination Input pen 2 is in contact with the touch surface 3a or not. Accordingly, the sensor controller 31 can update the contact state information of the active stylus 2 without waiting to receive the pen pressure value PRE via the pen tip communication or the short-range wireless communication.

In order to ensure that the sensor control 31 can receive both the first carrier signal and the second carrier signal, the sensor control 31 contains a detection circuit in which the frequency of the reference signal is the same as the frequency of the first carrier signal, and a detection circuit , at which the frequency of the reference signal is equal to the frequency of the second carrier signal. However, if the frequency difference between the first carrier signal and the second carrier signal is sufficiently small, such as, for example, if the first carrier signal is the 400 kHz signal described above and the second carrier signal is the 381 kHz or 421 kHz signal described above signal, the sensor controller 31 can also be designed to receive both the first carrier signal and the second carrier signal through a single detection circuit. That is, a detection circuit in which the frequency of the reference signal is 400 kHz, for example, can detect the 381 kHz and 421 kHz signals, but in this case, the phase output from the detection circuit changes gradually. The sensor controller 31 only needs to determine whether the carrier signal of the received downlink signal DSb is the first carrier signal or the second carrier signal according to the change in phase.

As described above, in the active stylus 2 and the position detection system 1 according to the present embodiment, since the contact state information can be sent by frequency modulation of the carrier signal of the downlink signal DSb, it is possible to avoid occurrence of a delay in updating the contact state information by the sensor controller 31 to suppress. When the sensor controller 31 is configured to sequentially supply the thus updated contact state information to the host processor 34, it is a case where the drawing application operated by the host processor 34 can perform a drawing operation without the pen pressure value PE, for example , possible to make the drawing application start drawing strokes without waiting for the pen pressure value PE to be delivered.

11 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 according to a modification example of the second embodiment of the present invention. The position detection system 1 according to the present modification example differs from the position detection system 1 according to the present embodiment in that the contact state information is sent separately from the pen pressure value PE in the data signal DATA using the downlink signal DSa instead of the downlink signal DSb. Below is a description that focuses on the differences.

An in 11 Position signal POS1d shown is the position signal POS1 sent by the active stylus 2 when it is in the contact state, and a position signal POS1u is the position signal POS sent by the active stylus 2 when it is in the floating state . Besides, this is in 11 The data signal DATAd shown is the data signal DATA sent by the active stylus 2 when it is in the contact state, and the data signal DATAu is the data signal DATA sent by the active stylus 2 when it is in the floating state.

The processing circuit 26d according to the present modification example is designed to generate the position signal POS1d and the data signal DATA1d based on the first carrier signal described above, and generate the position signal POS1u and the data signal DATAu based on the second carrier signal described above. More specifically, the processing circuit 26d is configured to obtain an unmodulated first carrier signal as the position signal POS1d and obtain an unmodulated second carrier signal as the position signal POS1u. Besides that , the processing circuit 26d is designed to obtain the first carrier signal modulated by data sent to the sensor controller 31 as the data signal DATA1d and the second carrier signal modulated by data sent to the sensor controller 31 as the data signal DATAlu .

The processing circuit 26d of the active stylus 2 according to the present modification example is designed to carry out the above-described carrier modulation process at a time (time t3) determined by a predetermined communication protocol using the reception time (time t2) of the uplink signal US received by the reception circuit 26c is decided as reference, begins and continuously executes the carrier modulation process over a period of time decided by the predetermined communication protocol.

11 shows an example in which the time t3 is equal to the time of start of transmission of the position signal POS1 and the carrier modulation process is carried out until the end of transmission of the data signal DATA. In this case, the signals generated by the processing circuit 26d in the carrier modulation process are any one or more of the position signals POS1d and POS1u and any one or more of the data signals DATAd and DATAu. However, the timing at which the processing circuit 26c starts the carrier modulation process and the period during which the carrier modulation process continues are not limited to this example. For example, the carrier modulation process may begin at the same time as the transmission of the position signal POS1, and the carrier modulation process may continue until the end of the transmission of the position signal POS1. In this case, the signal generated by the processing circuit 26d in the carrier modulation process is any one or more of the position signals POS1d and POS1u. In addition, the carrier modulation process may begin, for example, at the same time as the transmission of the data signal DATA, and the carrier modulation process may continue until the end of the transmission of the data signal DATA. In this case, the signal generated by the processing circuit 26d in the carrier modulation process is any one or more of the data signals DATAd and DATAu. In addition, the carrier modulation process may begin or end at the time the position signal POS1 is sent or at the time the data signal DATA is sent.

The sensor controller 31 according to the present modification example begins the process of determining whether the carrier signal of the downlink signal DSa received from the active input pen 2 is either the first carrier signal or the second carrier signal at the time determined by using the predetermined communication protocol the timing of the end of sending of the uplink signal US is decided as a reference, and continuously sequentially executes the determination process over the period of time decided by the predetermined communication protocol. The sensor controller 31 is designed so that it then sequentially determines, based on the result, whether the active input pen 2 is in contact with the touch surface 3a or not. Accordingly, the sensor controller 31 can update the contact state information of the active stylus 2 without waiting for the pen pressure value PRE to be obtained via the pen tip communication or the short-range wireless communication.

As described above, in the active stylus 2 and the position detection system 1 according to the present modification example, the contact state information can be sent separately from the pen pressure value PRE in the data signal DATA by frequency modulation of the carrier signal of the downlink signal DSa. It should be noted that the sending of the contact state information according to the present modification example (sending the contact state information via the downlink signal DSa) and the sending of the contact state information according to the present embodiment (sending the contact state information via the downlink signal DSb) can of course also be used together.

Next, a third embodiment of the present invention will be described in detail. A position detection system 1 according to the present embodiment differs from the position detection system 1 according to the second embodiment in that the contact state information is transmitted using a plurality of carrier signals having different phases instead of frequencies. Below is a description that focuses on the differences.

12 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting the position detection system 1 of the third embodiment of the present invention. The processing circuit 26d which failed in the nth frame Receiving uplink signal US and having entered the dual transmission mode performs processes that differ between an illustrated first period P1 and a second period P2, which is the period after the first period P1. Specifically, in the first period P1, the processing circuit 26d first generates the position signal POS2 based on the carrier signal having a predetermined phase. The position signal POS2 is none other than the position signal POS2 generated in a case where the carrier modulation process described above is not performed. On the other hand, the processing circuit 26d generates any one of the position signals POS2d and POS2u in the second period P2 by performing the above-described modulation process. The time length of the first period P1 is determined in advance by a predetermined communication protocol.

The carrier signal (the first carrier signal) constituting the position signal POS2d in the present embodiment is a signal whose phase difference from a carrier signal (a third carrier signal) constituting the position signal POS2 is a first value. On the other hand, the carrier signal (the second carrier signal) constituting the position signal POS2u in the present embodiment is a signal whose phase difference from the carrier signal (the third carrier signal) constituting the position signal POS2 is a second value different from the first Value differs. In a typical example, the first value is 0 degrees and the second value is 90 degrees or 180 degrees, but the first value can be 90 degrees or 180 degrees and the second value is 0 degrees. In addition, both the first value and the second value can be a value other than 0 degrees. It should be noted that in view of the possibility that a signal is sent from the user's hand holding the active stylus 2, the phase of which is 180 degrees from that of the signal sent from the pen tip electrode 21 , differs, it is cheaper to set the first value or the second value to 90 degrees instead of 180 degrees. However, when the signal sent from the user's hand can be excluded by a predetermined palm recognition process performed based on the receiving area of signals or the like, the first value or the second value may be 180 degrees.

The processing circuit 26d determines the state of the active stylus 2 based on the last acquired contact state information. The processing circuit 26d generates the position signal POS2d when the active stylus 2 is in the contact state, while generating the position signal POS2u when the active stylus 2 is in the contact state Stylus 2 is in the floating state and sends the generated signal as the downlink signal DSb. The transmission of the position signal POS2d or the position signal POS2u is carried out as in the second embodiment until the uplink signal US is received or until a predetermined time has elapsed since the last reception of the uplink signal US.

The sensor controller 31 according to the present embodiment is designed to detect the phase of the carrier signal of the received downlink signal DSb at each of a predetermined first time after the transmission of the uplink signal US and a second time after the first time. The first time is a time in the first time period P1 and the second time is a time in the second time period P2. The sensor controller 31 measures the time elapsed from the start of receiving the downlink signal DSb, and obtains the period until the expiration of a time length specified by a predetermined communication protocol as the first period P1, while obtaining the period after the end of the first period P1 as the second period P2, and sets the first point in time and the second point in time based on each acquired period.

The sensor controller 31, having acquired the phase of the carrier signal of the downlink signal DSb at each of the first time point and the second time point, determines whether or not the active stylus 2 is in contact with the touch surface 3a based on the detected phase difference. That is, when the detected phase difference is the above first value, this is determined as the contact state, and when the detected phase difference is the above second value, this is determined as the floating state. Accordingly, the sensor controller 31 can update the contact state information of the active stylus 2 without waiting to receive the pen pressure value PRE via the pen tip communication or the short-range wireless communication.

It is advantageous here if the sensor control 31 determines several second points in time and makes the above determination at every second point in time. In this way, the sensor controller 31 can determine more frequently whether the active stylus 2 is in contact with the touch surface 3a or not.

Since, as described above, the contact state information in the active stylus 2 and the position detection system 1 according to the present embodiment is through a phase modulation of the carrier signal of the downlink signal DSb, it is possible, as in the second embodiment, to suppress the occurrence of a delay in updating the contact state information by the sensor controller 31.

13 is a diagram showing signals sent and received between the active stylus 2 and the sensor controller 31 constituting a position detection system 1 according to a modification example of the present embodiment of the present invention. The position detection system 1 according to the present modification example differs from the position detection system 1 according to the present embodiment in that the contact state information is sent separately from the pen pressure value PE in the data signal DATA using the downlink signal DSa instead of the downlink signal DSb. Below is a description that focuses on the differences.

The processing circuit 31 according to the present modification example is designed to set the starting timings (the timings t5 and t6) of the first period P1 and the second period P2, respectively, at the timing specified by a predetermined communication protocol using the timing of reception (the timing t4) of the uplink signal US received by the receiving circuit 26c is decided as a reference.

13 shows an example in which the time t5 is equal to the time at which the position signal POS1 begins to be sent, and the time t6 is equal to the time at which the transmission of the DATA signal begins. The processing circuit 26c in this case generates the position signal POS1 based on the third carrier signal, while for the data signal DATA, it generates the data signal DATAd based on the first carrier signal when the contact state exists, and generates the data signal DATAu based on the second carrier signal , if the floating state exists. However, the starting timing of each of the first period P1 and the second period P2 decided by the processing circuit 26d is not limited to this example. For example, the time at which the second period P2 begins can be set to a time at which the position signal POS1 or the data signal DATA is sent.

The sensor controller 31 according to the present modification example decides the starting timing of each of the first period P1 and the second period P2 at the timing decided by the predetermined communication protocol using the timing of the end of transmission of the uplink signal US as a reference. The subsequent process is the same as that performed by the sensor controller 31 according to the present embodiment.

As described above, in the active stylus 2 and the position detection system 1 according to the present modification example, the contact state information can be sent separately from the pen pressure value PRE in the data signal DATA by phase modulation of the carrier signal of the downlink signal DSa. It should be noted that the sending of the contact state information according to the present modification example (sending the contact state information via the downlink signal DSa) and the sending of the contact state information according to the present embodiment (sending the contact state information via the downlink signal DSb) can of course also be used together.

Of course, although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments but can be embodied in various ways without departing from its spirit.

For example, in each of the above embodiments, an example in which sending the uplink signal US from the sensor controller 31 is performed by the capacitive coupling method has been described, but the uplink signal US may be sent by an electromagnetic induction method. In this case, the active input pen 2 is preferably provided with a coil for receiving the uplink signal US instead of the ring electrode 22 and the notch filter 27.

In addition, in each of the above-described embodiments, an example has been described in which the local identifier LID, the pen pressure value PRE, the switch information WS and the error detection code CRC are sent by the downlink signal DSc, but the downlink signal DSc need only be a signal that uses to send at least a part of the data signal sent from the active stylus 2 to the sensor controller 31, and some of these information items need not be sent or other information than these may be sent.

Furthermore, in each of the above-described embodiments, an example has been described in which the ring electrode 22 is used to detect the uplink signal US, but the downlink signal DS may also be sent from the ring electrode 22. In one example, the downlink signal DSa may be sent from the pin tip electrode 21 and the downlink signal DSb may be sent from the ring electrode 22. The processing circuit 26c in this case only needs to detect the uplink signal US using the pen tip electrode 21 while transmitting the downlink signal DSb.

In addition, the present invention is also applicable to a case where the transmission and reception of the uplink signal US and the downlink signal DS are carried out in time slot units. For example, a period of time (an empty period) in which the noise generated in the display 32 decreases is preferably used as the time slot. In this case, several time slots are defined in the frame described above.

14 is a diagram for illustrating signals sent and received between the active stylus 2 and the sensor controller 31 when transmitting and receiving the uplink signal US and the downlink signal DS are carried out in time slot units. 14 shows a case where the processing circuit 26d of the active stylus 2 performs the same carrier modulation process as in 10 explains, but the same also applies to a case in which the same carrier modulation process as in 11 until 13 is performed. How out 14 As can be understood, the active input pen 2 and the position detection system 1 can preferably carry out the above-described carrier modulation process even in a case where the transmission and reception of the uplink signal US and the downlink signal DS are carried out in time slot units.

DESCRIPTION OF REFERENCE SYMBOLS

1

Position detection system

2

active stylus

3

electronic device

3a

Touch surface

20

core body

21

Pen tip electrode

22

Ring electrode

23

Pressure sensor

24

Side switch

25

battery

26

integrated circuit

26a

Amplifier circuit

26b

Transmission circuit

26c

Receiving circuit

26d

Processing circuit

27

Barrier filter

28, 33

wireless communication unit

30

sensor

31

Sensor control

32

Advertisement

34

Host processor

COM

command

CRC

Error detection code

DATA

Data signal

DS, DSa to DSc

Downlink signal

GID

global identifier

LID, NLID

local identifier

POS 1, POS 2

Position signal

PRE

Pen pressure value

SW

Switch information

US

Uplink signal

Claims (25)

Active stylus pen, comprising a signal processing unit that performs sending a position signal and a data signal from a pen tip electrode and receiving a next uplink signal at a timing determined using a reception timing of an uplink signal received from a sensor controller as a reference timing; and a first wireless communication unit that performs short-range wireless communication with the sensor controller, the signal processing unit determining whether the next uplink is at that time signal has been received or not, and the signal processing unit, in a case where it is determined that the next uplink signal has not been received, sends at least a part of the data signal via the first wireless communication unit while sending the position signal from the pen tip electrode. Active stylus after Claim 1 , further comprising a pressure sensor that detects a pen pressure value, wherein the signal processing unit in a case where the pen pressure value detected by the pressure sensor indicates that the active stylus is in contact with a touch surface, a process of sending at least a part of the data signal via the first wireless communication unit performs while sending the position signal from the pen tip electrode. Active stylus after Claim 1 or 2 , wherein the signal processing unit switches the first wireless communication unit from a power saving mode to a normal mode before sending the at least part of the data signal via the first wireless communication unit. Active stylus after one of the Claims 1 until 3 , wherein the signal processing unit determines whether or not the next uplink signal has been received at that time, and in the case of determining that the next uplink signal has not been received, the signal processing unit sends the position signal from the pen tip electrode, performs an operation for detecting the uplink signal, and transitions to a dual transmission mode in which the at least part of the data signal is transmitted via the first wireless communication unit, and the signal processing unit transitions to the normal mode in a case where the uplink signal has been detected by the detection operation performed during the dual transmission mode the data signal is sent from the pen tip electrode. Position detection system, comprising the active input pen Claim 1 ; and the sensor controller, wherein the sensor controller data indicated by the data signal sent by the active stylus from the pen tip electrode and data indicated by the data signal sent by the active stylus via the first wireless communication unit than outputs data from the same active stylus to a host processor. Position detection system Claim 5 , wherein the sensor controller is connected to each of a sensor coupled to the pen tip electrode by capacitive coupling and a second wireless communication unit that performs short-range wireless communication with the active stylus, and via the sensor the position signal and the data signal sent by the pen tip electrode, while receiving the data signal sent by the active stylus via the first wireless communication unit via the second wireless communication unit. Position detection system Claim 5 , wherein the data signal sent by the active stylus from the pen tip electrode and the data signal sent by the active stylus via the first wireless communication unit contain common identification information, the sensor controller in a case where it receives the data signal, transmitted by the active stylus from the pen tip electrode, outputs active stylus transmission data contained in the data signal to the host processor in conjunction with the common identification information contained in the data signal, and the sensor controller in one In the case where it has received the data signal transmitted by the active stylus via the first wireless communication unit, the active stylus transmission data contained in the data signal in conjunction with the common identification information contained in the data signal , outputs to the host processor. Position detection system Claim 5 , wherein the active stylus further comprises a pressure sensor that detects a pen pressure value, the signal processing unit modulates the position signal using the pen pressure value detected by the pressure sensor, and the sensor controller in a case where the pen pressure value indicated by the position signal indicates, that the active stylus is not in contact with a touch surface, does not output active stylus transmission data included in the data signal sent by the active stylus via the first wireless communication unit to the host processor. Position detection system Claim 8 , where the signal processing unit is the position signal modulated by any of frequency modulation, spread spectrum and phase modulation. Integrated circuit used for an active stylus having a first wireless communication unit for performing short-range wireless communication with a sensor controller, wherein at a timing decided using a reception timing of an uplink signal received from the sensor controller as a reference timing, sending a position signal and a data signal from a pen tip electrode and receiving a next uplink signal are performed, and it is determined whether or not the next uplink signal has been received at the time, and in a case where it is determined that the next uplink signal has not been received, at least a part of the data signal is sent via the first wireless communication unit while the position signal is transmitted from sent to the pen tip electrode. Active stylus, comprising a processing circuit that generates a downlink signal to be sent to a sensor controller, and a transmission circuit that transmits the downlink signal by imparting a change to a potential of an electrode provided on a pen tip, wherein the processing circuit performs a carrier modulation process in which the downlink signal is generated based on a first carrier signal in a case where the active stylus is in a contact state, while the downlink signal is generated in a case where the active stylus is in a Floating state is generated on the basis of a second carrier signal that differs from the first carrier signal. Active stylus after Claim 11 , wherein the second carrier signal is a signal whose frequency is different from that of the first carrier signal. Active stylus after Claim 12 , further comprising a receiving circuit that receives an uplink signal transmitted by the sensor controller, the processing circuit performing the carrier modulation process in a case where the receiving circuit at a time using a reception timing of the uplink signal received by the receiving circuit when reference is decided, no next uplink signal is received. Active stylus after Claim 13 , wherein the downlink signal generated by the carrier modulation process is a position signal that is an unmodulated first carrier signal or an unmodulated second carrier signal. Active stylus after Claim 12 , further comprising a receiving circuit that receives an uplink signal transmitted by the sensor controller, the processing circuit starting the carrier modulation process at a timing decided using a reception timing of the uplink signal received by the receiving circuit as a reference. Active stylus after Claim 15 , wherein the downlink signal generated by the carrier modulation process is at least one of a position signal that is an unmodulated first carrier signal or an unmodulated second carrier signal and a data signal generated by modulating the first carrier signal or the second carrier signal by data , which are sent to the sensor control, is received. Active stylus after Claim 11 , wherein the second carrier signal is a signal whose phase is different from that of the first carrier signal. Active stylus after Claim 17 , wherein the processing circuit generates the downlink signal in a first period based on a third carrier signal having a predetermined phase while executing the carrier modulation process in a second period which is the period after the first period, the first carrier signal is a signal whose Phase difference from the third carrier signal is a first value, and the second carrier signal is a signal whose phase difference from the third carrier signal is a second value that differs from the first value. Active stylus after Claim 18 , further comprising a receiving circuit that receives an uplink signal sent by the sensor controller, wherein the processing circuit performs the carrier modulation process in a case where the receiving circuit does not receive a next uplink signal at a timing decided using a reception timing of the uplink signal received by the receiving circuit as a reference. Active stylus after Claim 19 , wherein the downlink signal generated based on the third carrier signal is a position signal that is an unmodulated third carrier signal, and the downlink signal generated by the carrier modulation process is a position signal that is an unmodulated first carrier signal or an unmodulated second Carrier signal is. Active stylus after Claim 18 , further comprising a receiving circuit that receives an uplink signal transmitted by the sensor controller, the processing circuit deciding a start time of each of the first period and the second period at a time determined using a reception time of the uplink signal transmitted by the Receiving circuit was received, as reference is decided. Active stylus after Claim 21 , wherein the downlink signal generated based on the third carrier signal is a position signal that is an unmodulated third carrier signal, and the downlink signal generated by the carrier modulation process is a data signal generated by modulating the first carrier signal or the second Carrier signal is obtained through data sent to the sensor controller. Position detection system, comprising the active input pen Claim 11 ; and the sensor controller, wherein the sensor controller determines whether a carrier signal of a downlink signal received by the active stylus is the first carrier signal or the second carrier signal, and based on the result of the determination, determines whether the active stylus is connected to a touch surface There is contact or not. Position detection system Claim 23 , wherein the second carrier signal is a signal whose frequency is different from that of the first carrier signal, and the sensor controller receives the downlink signal by a detection circuit that detects a predetermined frequency and according to a change in phase as a result of the reception by the Detection circuit is output, determines whether the carrier signal of the downlink signal is the first carrier signal or the second carrier signal. Position detection system, comprising the active input pen Claim 19 ; and the sensor controller, wherein the sensor controller detects a phase of a carrier signal of the downlink signal at each of a first time after transmission of the uplink signal and a second time after the first time and based on a difference between the phase of the carrier signal of the downlink signal at the first time and the phase of the carrier signal of the downlink signal at the second time determines whether or not the active stylus is in contact with a touch surface.

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